Page 115 - Lecture Notes DCC3113

8.1.4 The selection factors of junction types;

The principal factors influencing the design of a junction are:
i. Traffic volume and characteristics : an intersection should accomodate with comfort and safety
a design peak traffic volume. The needs of commercial vehicles should be considered.
ii. Topography and environment : the location and design of an intersection will be affected by
many factors including the allignment and grade of approach roads, the need to provide for
drainage, the extent of interference with public utilities, proper acces and the presence of local
features, both man-made natural.
iii. Economics – variotion to existing intersections should be justified by commensurate benefits to
traffic
iv. Human factors – in an intersection design, driver characteristics should be considered

8.1.5 Traffic light design and phases

Figure 8-9: Two Phase Cycle

Figure 8-10: Three Phase Cycle

Figure 8-11: Four Phase Cycle

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